JPH10250876A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the generation of wrinkles to recording paper at a downstream side part by positioning the conveying direction downstream side part of an auxiliary conveying member higher than a conveying direction upstream side part. SOLUTION: An auxiliary conveying member 306 is extended in a recording paper conveying direction (in an direction of an arrow mark (B), and a downstream side part 308 in the recording paper conveying direction from a lengthwise outer part is in a higher position than an upstream side part 310 in the recording paper conveying direction from the center part. The upper face 308a of the downstream side part 308 of the auxiliary conveying means 306 is positioned at the same height as the upper face 304a of two belts 304. A part, positioned between two belts 304, of recording paper is therefore positioned at the same height as a part adhering closely to the belts 304, and the recording paper becomes flat in a flapping dissolved state and is conveyed to a fixing roll as it is flat. As a result, wrinkles caused by flapping is not generated on the recording paper in a fixing device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as an electrophotographic copying machine, a printer or a facsimile.

[0002]

2. Description of the Related Art Conventionally, an image forming apparatus using an electrophotographic method has been widely used. In the electrophotographic image forming apparatus, for example, while rotating a drum-shaped image carrier (photoconductor) at a predetermined process speed, the photoconductor is uniformly charged by a charging device and recorded on a document. The photosensitive member is irradiated with light carrying image information to form an electrostatic latent image on the photosensitive member, and the electrostatic latent image is developed using a developer to form a developed image, and the developed image is recorded. This is a device that transfers the image to a recording medium such as paper and fixes the transferred image with a fixing device to obtain a print image (copy image).

[0003] Such an image forming apparatus usually includes a transport device for transporting a recording sheet from a transfer area (an example of a first area) where a developed image is transferred to the recording sheet to a fixing device (an example of a second area). Have. As a transporting device, for example, a device is known in which two parallel belts are hung on a driving roller and a driven roller separated by a predetermined distance, and the recording paper is transported while being brought into contact with the belt. In this device, a large number of holes are formed in two belts, and two metal plates with a large number of holes corresponding to these holes are provided inside the two belts so as to contact the two belts. Fixed. In addition, a suction fan is installed at the position between the two metal plates,
The suction fan conveys the recording paper while adsorbing the recording paper to the two belts.

Between the two belts, a rib (transportation assisting member) extending in parallel with the two belts and having an upper surface located at a position lower than the upper surfaces of the two belts is fixed to a fixed base. I have. Without these ribs, the recording paper being conveyed may come into contact with the sheet metal and the conveyance force may be reduced. Further, a transfer image is formed on the recording paper, and if the recording paper contacts the metal plate before fixing, the transfer image may be disturbed.

However, the recording paper may be attracted and wavy along the irregularities formed by the belt and the ribs. In this case, the recording paper is conveyed to the fixing device in a wavy state,
Wrinkles may occur on the recording paper.

[0006]

Therefore, the upper surface of the rib is positioned higher than the upper surfaces of the two belts to prevent the recording paper from waving. However, the ribs and the recording paper come into contact with each other, and the friction resulting from this contact reduces the conveying force. In particular, there is a problem that conveyance failure is likely to occur with a small-sized recording paper having a small area in contact with the belt.

SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide an image forming apparatus provided with a conveying device which does not generate wrinkles on a recording sheet and has a good conveying force.

[0008]

In order to achieve the above object, an image forming apparatus according to the present invention is provided with a conveying device for conveying a recording sheet from a predetermined first area to a second area. In the image forming apparatus to be formed, the transport device includes: (1) a pair of transport members arranged in parallel at a predetermined interval, which transport the recording paper from the first area to the second area while contacting the recording paper. (2) A transport assisting member disposed between the pair of transporting members and extending in the transporting direction, the transporting auxiliary member being located at a position higher on the downstream side in the transporting direction than on the upstream side in the transporting direction. It is.

[0009] Here, the transport assisting member includes: (3) a position where an upstream portion in the transport direction of the transport assisting member is located at a position lower than the transport member, and a position where a downstream portion in the transport direction is higher than the transport member. Alternatively, they may be located at the same height.

The transport assisting member may further comprise: (4) a portion where the trailing edge of the recording paper is located when the leading edge of the minimum length recording paper transported by the transport device reaches the second area. Alternatively, the height may be different on the upstream side in the transport direction from this portion.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an image forming apparatus according to the present invention will be described below with reference to the drawings.

First, an external configuration of a copying machine according to an embodiment of the present invention will be described with reference to FIGS.

FIG. 1 is a perspective view showing the appearance of a copying machine in which each door is closed, and FIG. 2 is a perspective view of the copying machine in which each door and the like are open as viewed from the front. FIG. 3B is a perspective view of the copying machine with the discharge door opened when viewed from the side, and FIG.
FIG. 7 is a perspective view schematically showing a state in which the front door is opened and the jammed recording paper 48 is taken out of the duplex conveying unit 176. On the top surface of a copying machine (which is an example of the image forming apparatus according to the present invention) 10, an openable and closable platen cover 12 is arranged. An operation unit (operation panel) 14 for inputting the number of copies and the like is arranged on the front side of the top surface. The operation unit 14 will be described later with reference to FIG. Note that a power switch 16 for turning on the power of the copying machine 10 is arranged next to the operation unit 14.

In the copying machine 10, an image can be formed on both sides of the recording paper, and two cassettes 18 and 20 each accommodating a plurality of recording papers are provided so as to be able to be taken in and out of the main body of the copying machine 10. The copying machine 10 also includes a manual feed tray 22 on which small-sized recording paper such as a postcard can be placed, and a paper discharge tray 26 on which recording paper on which an image is formed is stacked. The front door 2 is located above the two cassettes 18 and 20.
When the front door 28 is opened, as shown in FIG. 2, a fixing device knob 30, a total counter 32, a hopper 34, a developing device pressure lever 36, a registration knob 38, and a transport portion are provided. The release lever 40, the lateral registration knob 42, the double-sided transport handle lever 44, and the like appear.

On the left side of the copying machine 10, an openable and closable paper discharge door 46 is provided. The discharge door 46 has a first
And second discharge rollers 170 and 172 (see FIGS. 7 and 8)
When the discharge door 46 is opened, the first and second discharge rollers 170,
172 and the paper discharge tray 26 are separated from the copying machine main body. The paper discharge door 46 is opened and closed about a hinge 46 a formed below the paper discharge tray 26. This hinge portion 46a
Is formed at a position lower than the duplex conveying unit 176 (see FIGS. 7 and 8). Therefore, when the paper discharge door 46 is opened, as shown in FIG. 3A, a paper discharge unit 173 including first and second paper discharge rollers 170 and 172 is provided.
In addition, since the opening area is wide, the recording paper 48 existing in the double-sided conveyance unit 176 located below the paper discharge unit 173 can be sufficiently reached. Therefore, when the recording paper 48 is jammed in the paper ejection unit 173 or the duplex conveying unit 176, the jammed recording paper 48 can be easily removed by opening the paper ejection door 46. When the recording paper 48 is jammed in the back of the double-sided conveyance unit 176, as shown in FIG. I can remove it.

Referring to FIG. 4, details of the operation unit 14 will be described.

FIG. 4 is a plan view showing the operation unit 14.
Although it is shown as being divided into two parts at the center for the sake of space, it is actually rectangular.

A power switch 16 is arranged at the rightmost part of the operation unit 14. A start key 50 is arranged slightly to the left of the power switch 16. The start key 50 is pressed to start copying. A stop key 52 is disposed diagonally to the upper right of the start key 50. The stop key 52 is pressed to stop copying. On the upper left of the stop key 52,
A preheating key 54 is provided. This preheating key 54
The button is pressed when the copier 10 (see FIG. 1) is set in the preheated state or when the preheated state is released. A numeric keypad 56 is arranged on the left side of the start key 50. This numeric keypad 56
Is used for inputting the number of copies and a numerical value when setting a mode. An interrupt key 5 is provided at the lower right of the numeric keypad 56.
8 are arranged. The interrupt key 58 is depressed when interrupting a continuous copy and taking another copy. A clear key 60 is arranged at the lower left of the numeric keypad 56. The clear key 60 is pressed to clear the number of copies and the input for setting the mode. A reset key 62 is arranged at the upper left of the numeric keypad 56. The reset key 62 is pressed when returning the copy mode to the standard mode. Below the reset key 62, an ID key 64 is arranged. This ID key 64
Is pressed when registering a personal identification number and when inputting the registered personal identification number to make the copying machine copyable.

On the left side of the ID key 64, a zoom key 66 is arranged. The zoom key 66 is pressed when setting the zoom magnification. Above the zoom key 66, an automatic scaling key 68 is arranged. The auto scaling key 68 is pressed when setting / cancelling the auto scaling mode. On the left side of the zoom key 66, a paper selection key 70 is arranged. The paper selection key 70 is pressed to select a paper feeding position. On the right side of the auto zoom key 68, a percent key 69 is arranged. The percent key 69 is pressed to display the set magnification. Above the auto zoom key 68, a display unit 72 is arranged. The display unit 72 displays the number of copies / magnification and the setting state of the mode. On the left side of the display unit 72, a warning display 74 is arranged. The warning display 74 flashes when a predetermined control card is not securely set, when a paper jam occurs, when paper (recording paper) needs to be supplied, and when toner needs to be supplied.

Below the warning display 74, a paper selection / paper jam position display 76 is arranged. In the paper selection / paper jam position display 76, the selected cassette / multi feeder tray is turned on, and when a paper jam occurs, the position blinks. When a DF (document feeder: document feeder) is retrofitted, it flashes when a document jam occurs in the DF. Also, it lights up when it is necessary to inspect the sorter and the right door, which are also attached later. On the lower left side of the paper selection / paper jam position display 76, a reduction / enlargement key 78 is arranged. The reduction / enlargement key 78 is depressed at the time of setting reduction / enlargement of fixed magnification. An equal-size key 80 is arranged between the reduction / enlargement keys 78. The same-size key 80 is pressed to return the magnification to the same magnification (100%). On the left side of the reduction / enlargement key 78, a copy density key 8
2 are arranged. This copy density key 82 is pressed when manually adjusting the copy density.

AE is located between the copy density keys 82.
A key 84 is arranged. This AE key 84 is
Pressed when setting / cancelling (automatic density adjustment) mode. Above the copy density key 82, a double-sided key 86 is arranged. The double-sided key 86 is pressed when setting / releasing the double-sided mode. On the left side of the double-sided key 86, the sorter key 8
8 are arranged. This sorter key 88 is sorted,
Pressed when selecting or canceling staple sort or group mode. On the left side of the copy density key 82, a document mixed key 90 is arranged. This mixed original key 90 is
Pressed when setting / releasing the mixed document mode. On the left side of the mixed original key 90, a frame erase key 92 is arranged.
The frame erasing key 92 is pressed when setting or canceling the frame erasing mode. On the left side of the frame erase key 92, a binding margin key 94
Is arranged. The binding margin key 94 is pressed when setting or canceling the binding margin mode. On the left side of the binding margin key 94, a mode memory key 96 is arranged. The mode memory key 96 is pressed when registering / calling a copy mode. Up to three arbitrary modes can be registered in the mode memory.

Above the mode memory key 96, an OK key 98 is arranged. The OK key 98 is pressed to confirm the set item or function during mode setting. Above the OK key 98, a user mode key 100
Is arranged. The user mode key 100 is pressed when setting or canceling the user mode.
On the right side of the OK key 98, a reduced layout key 102 is arranged. The reduced layout key 102 is pressed when setting / releasing the reduced layout mode. On the right side of the reduced layout key 102, a page continuous shooting key 104
Is arranged. The page continuous shooting key 104 is pressed when setting or canceling the page continuous shooting mode. An even / odd key 106 is arranged on the right side of the page continuous shooting key 104. The even / odd key 106 is pressed when setting the odd / even number of documents. Warning display 74, paper selection /
Paper jam position display 76, double-sided key 86, sorter key 88
Above, such as an elongated message display 108
Is arranged. This message display 108
When the document needs to be set on the DF, when it is necessary to specify the border erase width / binding margin, when the document needs to be replaced,
When it is necessary to press the start key 50, when the number of copies exceeds the limit, the display blinks while displaying the contents of each.

A user mode which can be set by pressing the above-mentioned user mode key 100 will be described.

The change of the auto clear time can be set.
In this setting, the auto clear time can be set in a unit of one minute in a range of 0 to 9 minutes. If the time is set to 0 minutes, the auto clear does not function. The display unit 72 displays “U
01 "is displayed.

The change of the auto power off time can be set. In this setting, the auto power-off time can be set in the range of 10 minutes to 120 minutes in units of 10 minutes. “U02” is displayed on the display unit 72.

A preheating mode can be set. In this setting, the power consumption in the preheating mode can be selected from 10% power saving and 50% power saving. “U03” is displayed on the display section 72.

ON / OFF of automatic selection of a cassette can be set. This setting is based on the auto paper selection (A
PS) / auto cassette change (ACC). ON is APS /
ACC symmetry, OFF is APS / A
That is, the CC should not be symmetric. The display unit 72 displays “U0
4 "is displayed.

ON / OFF of hand size designation can be set. This setting selects whether to register the paper size of the multi-feeder at the time of paper setting or to register when the start key 50 is pressed. ON means registering when paper is set, and OFF means registering when the start key 50 is pressed. The display unit 72 displays “U0
5 "is displayed.

ON / OFF of automatic sorting can be set.
This setting is used to select whether or not to perform automatic sorting when a plurality of documents are present. ON means that automatic sorting is performed, and OFF means that automatic sorting is not performed. “U06” is displayed on the display unit 72.

It is possible to set ON / OFF of one original sorting. This setting is used to select whether or not to sort when the number of documents is one. ON means that one document is sorted, and OFF means that one document is not sorted. “U07” is displayed on the display unit 72.

ON / OFF of the feeder irregular size can be set. This setting is used to select whether an image is missing or not when a document of an irregular size is used. ON is
OFF means that image missing is not performed. “U08” is displayed on the display unit 72.

The default value of the margin width can be changed. As a result, the default value of the binding margin width is from 0 mm to 20 m.
m can be set in 1 mm units. “U09” is displayed on the display section 72.

ON / OFF of the setting can be set only for the back side of the binding margin. This setting is for setting whether or not to create a binding margin only on the back side when performing "double-sided / single-sided copying" of a document having a binding margin in the "binding margin mode". ON is to make a binding margin only on the back side, and OFF is to make a binding margin on both sides. “U10” is displayed on the display section 72.

The input unit can be switched between millimeters and inches. Specifies whether the input length unit is millimeters or inches. -1 means millimeter input, and -0 means inch input. “U11” is displayed on the display section 72.

The user mode can be initialized. Initialize the user mode settings. To initialize, the user presses the OK key 98 and the user mode key 100 successively. Display 7
2 displays “U00”.

The standard mode can be registered. Reset key 6
The mode selected when 2 is pressed is registered. To register, the user presses the OK key 98 and the user mode key 100 successively. “U98” is displayed on the display section 72.

The standard mode can be initialized. Return the standard mode to the factory default. OK key 9 to initialize
8. Press the user mode 100 continuously. “U99” is displayed on the display section 72.

The density can be corrected. When the copy density is high or low, the density can be corrected in a range of ± 8 steps. “U21” is displayed on the display unit 72. In addition, zoom fine adjustment can be set. When an error occurs between the size of the original document and the size of the copy image at the same magnification, fine adjustment can be performed to eliminate the error. X direction (enlarged) /
The Y direction (reduction) can be set independently in the range of 99 to 101% in 0.2% units. When the display is enlarged,
“U22” is displayed in 2. At the time of reduction, the display unit 7
2 displays “U23”.

The setting for cleaning the feeder can be made.
With this setting, the feeder / transport unit 162 of the feeder can be cleaned. “U24” is displayed on the display section 72. You can set the cleaning of the wire. With this setting, the transfer charging line can be automatically cleaned. The display unit 72 displays “U2
5 "is displayed.

An example of what is displayed on the display unit will be described with reference to FIGS.

FIG. 5 is an explanatory diagram showing an example of changing the above-described auto power off time, and shows a display section 72 (see FIG. 4).
Are shown in segments. FIG. 6 is an explanatory diagram showing a procedure for inputting a password.

In the normal copy mode, "1" is displayed on the display section 72 as shown in FIG.
0). To change the auto power off time, first, the user mode key 100 (see FIG. 4) is pressed to display the user mode number “U01” on the display unit 72 (501). Next, "0" and "2" of the ten keys 56 are sequentially pressed to display the user mode number "U02" on the display unit 72 (502). Next, press the OK key 98,
The current setting value “10” of the user mode number “U02” is displayed on the display unit 72 (503). By pressing the "+" key or the "-" key, a desired set value is displayed on the display section 72 (504). The figure shows an example of 60 minutes. When resetting, the clear key 60 is pressed to set a desired numerical value.
When the changed setting value is sufficient, the user presses the OK key 98. As a result, the changed set value is stored, and the user mode number “U02” is displayed on the display unit 72 (505).
Next, the user presses the user mode key 100 to display “1” on the display section 72. This completes the change of the auto power off time. If the reset key 62 is pressed during the user mode, the process exits the user mode and returns to the standard mode.

The input of the personal identification number will be described.

In the ID mode, the power switch 16 (FIG. 4)
6), “1d” is displayed on the display section 72 as shown in FIG. 6 (600). "1" is displayed on the display 72.
If "d" is displayed, copying cannot be performed unless a four-digit password is entered. Then, the ten key 56 is pressed to input the password. After entering one digit of PIN,
"1d-" is displayed on the display section 72 (601). When the next one digit of the password is input, "1d7 (actually, one horizontal segment and one vertical segment)" is displayed on the display section 72 (602). When the next one digit is input, "1d" is displayed on the display section 72 (60).
3). When the last one digit is input, “1d b” is displayed on the display section 72.
Is displayed (604), and copying can be performed. If a wrong password is entered, the user inputs the correct password by pressing the clear key 60.

Referring to FIGS. 7, 8 and 9, an outline of the internal configuration of the copying machine 10 of FIG. 1 and a basic image forming operation will be described.

FIG. 7 is a schematic diagram showing the internal structure of the copying machine 10, and FIG. 8 is a schematic diagram showing a recording paper transport path. FIG. 9 is a schematic diagram showing the drive system of each motor. In the figure, lines in which black and white are alternately drawn represent transmission of mechanical drive, and white arrows indicate the flow of electric signals. Represents

When the power switch 16 (see FIG. 1) is turned on, the copying machine 10 enters a copyable state (standby state). In this standby state, the operation unit 14
Is operated, the user selects which of the cassettes 18, 20 and the manual feed tray 22 the recording paper is fed from. By selecting the automatic paper size selection mode (APS mode) with the operation unit 14, the cassette 1
The recording paper is automatically fed from any one of the trays 8 and 20 and the manual feed tray 22. Here, the case where the recording paper stored in the cassette 18 is selected will be described. However, even when the recording paper in the cassette 20 or the manual feed tray 22 is selected, the operation is substantially the same.

When the copy start button of the operation unit 14 is pressed, the main motor (M1) 110 starts rotating, and only one sheet of the recording paper 18a stored in the cassette 18 is fed by the pickup roller 112 and fed. The roller 114 is held between the roller 114 and the separation roller 116 and is conveyed. Further, the registration roller 1 is stopped by the first vertical path roller 118 and the second vertical path roller 120.
It is transported to 22. Immediately before the registration roller 122 (slightly upstream in the recording paper transport direction), a pre-registration sensor 124 for detecting the recording paper is disposed, and a predetermined time has elapsed since the recording paper was detected by the pre-registration sensor 124. After that, the first vertical pass roller 118 and the second vertical pass roller 1
Stop rotation of 20. As a result, the recording paper is moved to the first position while the leading end of the recording paper remains in contact with the registration roller 122.
Since the paper is conveyed by the vertical path roller 118 and the second vertical path roller 120 for a predetermined time, the distance between the registration roller 122 and the first vertical path roller 118 is about 10 m.
m recording paper loops are formed. By forming this loop, the leading edge of the recording paper is aligned with the nip portion of the registration roller 122, so that the skew of the recording paper can be corrected. The main motor 110 is controlled by the DC controller 300 in the same manner as a paper discharge motor (M6) 184 and a setback motor (M7) 188 described later.

The registration rollers 122 are arranged to adjust the position of the recording paper and the position of the image on the photosensitive drum 126 so that an image is formed at an appropriate position from the leading end of the recording paper. As described above, the recording paper conveyed to the registration roller 122 is in a standby state in a state where the leading end thereof contacts the registration roller 122 to form a loop, and is synchronized with the timing at which the toner image reaches the transfer area 128. The recording paper is transported to the transfer area 128.

Immediately before the first vertical path roller 118 (slightly upstream of the first vertical path roller 118 in the recording paper transport direction), a vertical path sensor 130 for detecting the recording paper being transported is arranged. After a lapse of a predetermined time from the timing when the recording paper is detected by the vertical path sensor 130,
The document illumination lamp 132 is turned on, and the document (not shown) placed on the document table glass 13 starts to be illuminated. This is the start of the image forming operation. Document illumination lamp 132
Is mounted in a scanner unit 134, and the scanner unit 134 is arranged below the platen glass.

As shown in FIG. 7, the scanner unit 13
Reference numeral 4 denotes a first mirror unit 138 having a document illumination lamp 132 and a first mirror 136, a second mirror 140 and a third mirror unit 138.
Second mirror unit 144 having mirror 142, lens drive system 146, fourth mirror 148, fifth mirror 1
50 and a sixth mirror 152. When illuminating a document, an optical motor (not shown) for scanning the scanner unit 134 is rotated. The reflected light from the document is converted into an image signal by a first mirror 136, a second mirror 140, a third mirror 142, a lens driving system 146, and a fourth mirror 14.
The light is irradiated onto the photosensitive drum 126 through the eighth mirror 150, the sixth mirror 152, and the photosensitive drum 126.
Is formed on the original image. The configuration of the lens driving system 146 will be described later.

The photosensitive drum 126 has a rotation shaft extending in a direction perpendicular to the plane of the paper of FIG. The photosensitive drum 126 is located upstream of the irradiation position where the reflected light from the document is irradiated in the rotation direction of the photosensitive drum 126.
A primary charger 154 for uniformly charging 6 is provided. The photosensitive drum 126 is uniformly charged by the primary charger 154 to form a charged surface. On this charged surface,
The reflected light from the document is irradiated to form an electrostatic latent image.

A developing device 156 for developing an electrostatic latent image is located downstream of the irradiation position in the rotation direction of the photosensitive drum 126.
Is arranged. A region where the photosensitive drum 126 and the developing device 156 face each other is a developing region where the electrostatic latent image is developed. When the electrostatic latent image reaches the developing area by the rotation of the photosensitive drum 126, toner is supplied to the electrostatic latent image from the developing sleeve 158 to form a toner image (developed image).

A transfer charger 160 for transferring a toner image to recording paper is disposed downstream of the developing site in the rotation direction of the photosensitive drum 126. The area where the photosensitive drum 126 and the transfer charger 160 face each other is a transfer area 128 where the toner image is transferred to the recording paper. Before the toner image reaches the transfer area 128 due to the rotation of the photosensitive drum 126,
At a predetermined timing, the registration roller 122 starts rotating, and conveys the recording paper to the transfer area 128. Transfer area 1
The toner image is transferred to the recording paper conveyed to.
The recording paper onto which the toner image has been transferred is separated from the photosensitive drum 126 by a static elimination needle (not shown), transported to a transport unit 162 rotating in the direction of arrow B, and transported to a fixing device 164. A separation sensor 166 that detects whether the recording paper has been normally separated from the photosensitive drum 126 is disposed slightly downstream in the recording paper conveyance direction from the position where the recording paper is separated from the photosensitive drum 126. I have.

On the other hand, about 90% of the toner from the surface of the photosensitive drum 126 is transferred to the recording paper, but the remaining toner remains on the photosensitive drum 126. The remaining toner is removed from the photosensitive drum 126 by a cleaner (not shown). The residual charges remaining on the photosensitive drum 126 are discharged by a discharge lamp (not shown). As a result, the photosensitive drum 126 is ready for the next image formation.

In order to reliably fix the toner electrostatically adhered to the surface of the recording paper to the surface, the recording paper is transported to the conveying section 162.
To the fixing device 164. In the fixing device 164,
The toner adhering to the recording paper comes into contact with the high-temperature fixing roller 168 and melts, and the fine iron powder contained in the toner pierces the recording paper in a wedge shape, whereby the toner is reliably fixed to the recording paper.

The recording paper that has passed through the fixing device 164 has a strong tendency to curl under the influence of high temperature and pressure by the fixing roller 168. For this reason, immediately after the recording paper has passed through the fixing device 164, the leading end of the recording paper is nipped by the first paper discharge roller 170, and the first paper discharge roller 170 is rotated faster than the fixing roller 168 to be conveyed. Thereby, the fixing roller 168
The recording paper is apparently pulled between the first discharge roller 170 and the recording paper. However, since the pressure at which the first paper discharge roller 170 nips the recording paper is set lower than the pressure at which the fixing roller 168 nips the recording paper, the recording paper is slipped at the first paper discharge roller 170. As long as the recording paper is held between the fixing rollers 168, the recording paper is conveyed according to the rotation speed of the fixing roller 168. After the recording paper is separated from the fixing roller 168, the recording paper is discharged outside the apparatus by the first and second discharge rollers 170 and 172. In addition,
Immediately after the first paper discharge roller 170 (slightly downstream in the recording paper discharge direction from the first paper discharge roller 170), a paper discharge sensor 174 for detecting a recording paper is arranged.

As described above, the copying machine 10 can also form an image on the back of a recording sheet. Whether the image is formed on one side of the recording paper (single-sided copy) or the image is formed on both sides (two-sided copy) is determined by the operation unit 14 before the operator starts the operation. The basic image forming operation for both one-sided copying and two-sided copying is performed by the above-described process.
In the case of single-sided copying, the process ends when the recording paper is discharged outside the apparatus. The two-sided copy will be described.

Below the transport section 162, there is arranged a duplex transport unit 176 for loading the recording paper copied on one side and transporting it so as to copy on the other side. The two-sided conveyance unit 176 includes first and second setback rollers 178 and 180, which will be described later, and the recording paper sent from the fixing device 164 is moved by the first and second discharge rollers 170 and 172. It is transported to the duplex transport unit 176. The two-sided conveying unit 176 has an oil absorbing pad 216 as described later.
Is attached.

Paper discharge sensor 174 and second paper discharge roller 172
And a back-feed prevention mylar 1 for preventing back-feeding of the recording paper.
82 (see FIG. 21). Therefore, the first
The leading end of the recording paper that has passed through the paper discharge roller 170 is immediately detected by the paper discharge sensor 174, and the reverse feed prevention mylar 182
And is sent to the second discharge roller 172. Further, the timing at which the leading edge of the recording paper is detected by the paper ejection sensor 174 and the timing at which the trailing edge of the recording paper obtained based on the recording paper size data passes through the fixing roller 168 are calculated. Then, at the timing when the recording paper has passed the fixing roller 168, the paper feed speed of the second paper discharge roller 172 is made faster than the paper feed speed of the first paper discharge roller 170. The driving source of the second discharge roller 172 is a discharge motor (M6) 184, and the first discharge roller 1
70 are driven by the photosensitive drum 126 and the fixing roller 168.
Is the same main motor 110 as the drive of the main motor. Therefore,
The first paper discharge roller 170 and the second paper discharge roller 172 use different driving sources. For this reason, the paper feed speeds of the first discharge roller 170 and the second discharge roller 172 can be made different. Here, the paper ejection sensor 174
When the time required for the trailing edge of the recording paper to pass through the fixing roller 168 from when the leading edge of the recording paper is detected has elapsed, the paper feed speed of the paper ejection motor 184 is changed and the second paper ejection roller 1 is changed.
The paper feed speed of the first paper discharge roller 170 was made higher than that of the first paper discharge roller 170.

The force by which the second discharge roller 172 pinches the recording sheet is configured to be stronger than that of the first discharge roller 170. This configuration is also a configuration for correcting the curl of the recording paper described above. In this configuration, the feed speed of the recording paper depends on the second discharge roller 172, and the recording paper is in an extended state between the first discharge roller 170 and the second discharge roller 172. The recording paper slips at the first paper discharge roller 170, and the curl of the recording paper is corrected. In this way, the recording paper is sent out of the apparatus from the leading end while being nipped by the second paper discharge roller 172. Immediately after the trailing edge of the recording sheet has passed through the first ejection roller 170, the sheet ejection sensor 174 detects the trailing edge of the recording sheet. Based on the timing of this detection and the paper feed speed, the trailing end of the recording paper passes through the reverse feed prevention mylar 182 and is located about 10 mm before the position of the second discharge roller 172 (upstream in the recording paper discharge direction). At this point, the discharge motor 184 is stopped and the second discharge roller 172 is stopped.

In the case of the one-sided copy mode, the copying operation is completed when the recording paper is discharged outside the apparatus at the feed speed of the second discharge roller 172. In a case where copying is performed on a plurality of recording sheets, the above-described operation is repeated at predetermined intervals, and the copying operation ends when the rear end of the final sheet is discharged outside the apparatus.

In the case of the double-sided copy mode, the recording paper returns to the inside of the machine without being discharged outside the machine. The outline of this operation will be described.
The details of this operation will be described later.

As described above, the trailing end is the paper discharge sensor 174.
Is sent by the second discharge roller 172,
When the trailing edge of the recording sheet passes through the reverse feed prevention mylar 182 and reaches about 10 mm before the position of the second discharge roller 172, the second discharge roller 172 is stopped. Next, the second paper discharging roller 172 is rotated (reversely rotated) so that the recording paper is conveyed in a direction opposite to the paper discharging direction. As a result, the trailing edge of the recording paper up to now becomes the leading edge of the recording paper, and the lower transport entrance roller 1
It is conveyed toward 86. The speed of this conveyance is about twice the rotation speed of the photosensitive drum 126, and the second paper discharge roller 172 conveys the recording paper quickly and removes it from the conveyance path between the fixing and the paper discharge. As a result, the next recording paper can be sent out to the second paper discharge roller 172, so that a plurality of recording papers can be efficiently conveyed.

By reversing the second paper discharge roller 172, the recording paper is guided by the reverse feed prevention
The paper is sent not to the paper discharge roller 170 but to the lower conveyance entrance roller 186. As will be described later, the lower conveyance entrance roller 186 is rotated by the driving of the paper discharge motor 184 when the second paper discharge roller 172 is rotating reversely (rotation for conveying the recording paper in the direction opposite to the paper discharge direction). I do. On the other hand, when the second paper discharge roller 172 is rotating forward, it is configured to rotate by the drive of the setback motor (M7) 188. The forward rotation of the setback roller described below refers to the first and second setback rollers 178 and 18.
Numeral 0 indicates rotation when the recording paper is conveyed toward the right side in FIG.

The leading edge of the recording paper held by the lower transport entrance roller 186 is detected by the lower transport sensor 190 and the first
It is sent to the setback roller 178. When the leading edge of the recording paper reaches the first setback roller 178, the first setback roller 178 has stopped. When the recording paper reaches the first setback roller 178 and the recording paper is fed by a predetermined amount from the lower conveyance sensor 190,
The lower transport entrance roller 186 is stopped. As a result, a loop of recording paper is formed about 10 mm between the lower conveyance inlet roller 186 and the first setback roller 178. The reason for forming the loop in this way is to correct the skew of the recording paper conveyed to the first setback roller 178.

At this time, the trailing end of the recording paper has passed through the second paper discharge roller 172. Therefore, the discharge motor 184
Can rotate the second paper discharge roller 172 forward again. In this case, as described above, since the discharge motor 184 and the lower conveyance inlet roller 186 are connected by a one-way bearing, the driving force of the discharge motor 184 is not transmitted to the lower conveyance inlet roller 186. Therefore, the second paper discharge roller 172 and the lower conveyance entrance roller 186 are rotated independently in the opposite direction, and the second paper discharge roller 172 can receive the next recording paper.

The lower conveyance inlet roller 186 is connected to a paper discharge motor 184 via a one-way bearing, and only when the paper discharge motor 184 rotates in the reverse direction, the lower discharge roller 186 is rotated.
4 is transmitted to the lower conveyance entrance roller 186. In the driving of the setback motor 188, the first and second setback rollers 178,
Only the drive for rotating the motor 180 forward is the lower conveyance inlet roller 186.
A one-way bearing is provided and connected between the setback motor 188 and the lower conveyance entrance roller 186 so that the transmission is performed. Both the first and second setback rollers 178, 180
The rotation of 8 works in exactly the same way. As described above, when the first and second setback rollers 178 and 180 start rotating forward, the lower conveyance inlet roller 186 also starts to rotate in the same direction, and the recording paper is rotated by the first and second setback rollers 17.
8,180.

The first and second setback rollers 178,
When 180 rotates forward, the lower transport inlet roller 186 feeds out the recording paper, and the first setback roller 178 sandwiches the recording paper and transports it toward the second setback roller. Immediately after the lower conveyance inlet roller 186 (slightly downstream in the recording paper conveyance direction), the above-described lower conveyance sensor 190 that detects the rear end of the recording paper is disposed. Is detected. Subsequent operations of the first and second setback rollers 178, 180 and the like are different when performing double-sided copying on one sheet of recording paper and when continuously performing double-sided copying on a plurality of recording sheets. Since the operation when performing double-sided copying on a plurality of recording sheets continuously will be described later, the operation when performing double-sided copying on one recording sheet will be described here.

If the leading edge of the recording paper reaches the setback sensor 196 before the trailing edge of the recording paper passes the transport branch point 187 located immediately after the lower transport sensor 190, the flapper solenoid (SL7) 192 is turned on. Then, the flapper 194 is lowered. Thereby, the recording paper is flapper 19.
4 while being guided. When the trailing edge of the recording paper passes through the lower conveyance entrance roller 186, the first and second setback rollers 178 and 180 are stopped, and thereafter, are reversed.
Due to this reverse rotation, the recording paper is conveyed toward the left side in the figure, but the leading end of the recording paper is located at a predetermined position before the setback sensor 196 (for example, 5 before the setback sensor 196).
mm), the first and second setback rollers 178 and 180 are stopped. The flapper 194
Is turned off after a lapse of a predetermined time since the recording paper starts being guided by the flapper 194. In this state, the copier 10
Is in a standby state for backside copy, and a message is displayed on the operation unit 14 (see FIG. 4) on the message display 108 to change the original.

On the other hand, when the trailing edge of the recording sheet has not reached the setback sensor 196 when the trailing edge of the recording sheet has passed the transport branch point 187 located immediately after the lower transport sensor 190, the leading edge of the recording sheet has reached the setback sensor 196. The first and second setback rollers 178 and 180 are rotated forward until they reach 196. When the leading edge of the recording paper is detected by the setback sensor 196, the first and second setback rollers 17
8, 180 are once stopped and then reversed. First
When the recording paper is fed backward by reversing the second setback rollers 178 and 180, and the leading end of the recording paper reaches a predetermined position before the setback sensor 196 (for example, a position 5 mm before the setback sensor 196), First and second
The setback rollers 178 and 180 are stopped. In this state, the copier 10 is in a standby state for backside copying, and a message is displayed on the operation unit 14 (see FIG. 4) on the message display 108 so as to change the original. In the example above,
Although the case is classified according to the position of the trailing edge of the recording paper, the present invention is not limited to this.
The sheet may be transported to a separation position described later and wait for backside copying.

When the operator changes the original and presses the copy start key again, the first and second setback rollers 17 are pressed.
8, 180 starts to rotate forward, and the recording paper is again conveyed by the first and second setback rollers 178, 180, and is fed again. At this time, the rotation speed of the first and second setback rollers 178 and 180 is about one half of the rotation speed during normal operation, and the recording paper is conveyed at a relatively low speed. This is because the leading edge of the recording paper is
This is for accurate detection and control in step 6.

After a lapse of a predetermined time since the leading edge of the recording paper is accurately detected by the setback sensor 196, the first and second setback rollers 178 and 180 are stopped, and the flapper solenoid 192 is turned on to turn on the flapper 19.
Lower 4. As a result, the flapper 194 is brought into contact with the recording paper at a position 4 mm after the leading end of the recording paper. However, in the copying machine 10, since a plurality of recording papers are stacked while shifting the leading end by 8 mm, as described later, the flapper is lowered to a position of 4 mm which is the center of the deviation. On the other hand, when the number of recording sheets is one, it is not always necessary to lower the flapper at a position of 4 mm.

When the flapper 194 is lowered onto the recording paper, the first and second setback rollers 178 and 180 start rotating forward. Simultaneously with the start of normal rotation (the speed at the time of normal conveyance, which is substantially equal to the rotation speed of the photosensitive drum),
The lower transport outlet roller clutch (CL7) 198 is turned on to rotate the lower transport outlet roller 200. After a lapse of a predetermined time (time during which the recording paper has moved over 4 mm) from the start of rotation of the first and second setback rollers 178 and 180, the flapper solenoid 192 is turned off and the flapper 194 is raised.

The recording paper re-fed by the lower conveyance exit roller 200 reaches the horizontal registration roller 202. When the recording paper reaches the horizontal registration roller 202, the horizontal registration roller 202 is stopped, but the recording paper is fed by a predetermined amount by the lower conveyance exit roller 200. This allows
A loop of recording paper is formed between the lower conveyance exit roller 200 and the horizontal registration roller 202. With this loop formed, start rotating the lateral registration roller 202,
The conveyance of the recording paper toward the registration roller 122 starts.

When an image is formed on one side, the first vertical pass roller 118 and the registration roller 12 are fed from the cassette until they enter the duplex conveying unit and are fed again.
2. Due to the correction of the skew between the first setback roller 178 and the horizontal registration roller 202, the recording paper may be displaced in the width direction (the direction perpendicular to the recording paper conveyance direction). Therefore, the lateral registration roller 202 is controlled so as to move in the axial direction so that the deviation can be corrected.

FIGS. 10 and 11 show this configuration. FIG.
This will be described with reference to FIG.

FIG. 10 is a perspective view showing components in the vicinity of a horizontal registration roller, a horizontal registration motor, and the like. FIG. 11 is a schematic diagram showing the horizontal registration sensor 206. Also, FIG.
FIG. 3 is a schematic diagram showing a lateral registration roller home position sensor 214.

The recording paper 20 is shifted more than the horizontal registration rollers 202.
On the slightly upstream side in the transport direction (arrow B direction) of No. 4, a lateral registration sensor 206 that detects a shift in the lateral direction (width direction) of the recording paper when re-feeding in the duplex mode is disposed. Based on the detection result of the lateral registration sensor 206, the lateral registration roller 2
02 is controlled to move in the axial direction.

The movement of the horizontal registration sensor 206 and the movement of the horizontal registration roller 202 are selected by a horizontal registration solenoid 208. The driving of the lateral registration motor 210 is performed by a driver of a first motor controller (not shown) under the control of the DC controller 300.

In correcting the displacement of the recording paper in the width direction, first, when the power is turned on, the light shielding plate located at the home position (HP) of the horizontal registration sensor 206 is moved to the horizontal registration sensor 20.
The lateral registration sensor 206 is moved until the position 6 is detected. The movement of the lateral registration sensor 206 corresponds to the lateral registration solenoid 2
08 is driven by rotating the lateral registration motor 210. When copying is performed in the duplex mode, the lateral registration solenoid 208 is driven in the same manner as described above in accordance with the width of the selected recording sheet.
0 is rotated in the reverse direction to move the lateral registration sensor 206. Thereafter, the home position is not detected until the power is turned off and turned on again, and the home position is relatively moved from the current position to a position corresponding to the width of the selected recording paper for each copy in the duplex mode. .

In the horizontal registration roller 202, the rotation of the horizontal registration roller 202 itself is driven by the drive of the main motor 110, and the rotation / stop is controlled by a horizontal registration clutch 212 (see FIG. 9). When the horizontal registration roller 202 holds the recording paper 204, the horizontal registration roller 202 moves in a direction orthogonal to the recording paper conveyance direction (the direction of arrow B), and thereby the recording paper 2.
04 moves in the width direction (lateral direction). This move
This is performed by rotating the lateral registration motor 210 while the lateral registration solenoid 208 is not driven.

The position of the horizontal registration roller 202 is determined with reference to the horizontal registration roller home position sensor 214. The position of the lateral registration roller 202 can be moved by 6 mm in both directions with respect to the position of the lateral registration home position sensor 214. The lateral registration motor 210 is rotated so that the lateral registration sensor 206 detects the end of the recording paper 204 while the recording paper is being conveyed. The home position of the lateral registration roller 202 is moved for each sheet.

According to the above configuration, before the image is transferred to the other side of the recording sheet having the image formed on one side, the position in the width direction of the recording sheet is adjusted, and the image is adjusted to the correct position on the recording sheet. Is formed. The reason why the loop of the recording paper is formed between the lower conveyance exit roller 200 and the horizontal registration roller 202 is not only for correcting the skew of the recording paper but also for adjusting the deviation in the width direction of the recording paper. This is to prevent the recording paper from being stressed, for example, when the recording paper is pulled.

A pre-lateral registration sensor 124 for detecting a recording sheet is disposed slightly upstream of the horizontal registration roller 202 in the recording paper conveyance direction (immediately before the horizontal registration roller 202). After a lapse of a predetermined time from the point when the sensor 124 detects the recording paper, the original illumination lamp 132
Lights up, and an image is formed on the recording paper. This process is similar to the process in which an image is formed on one side of the recording paper. In this way, an image is formed on both sides of the recording paper, and the recording paper is ejected outside the apparatus, thereby completing the copying operation.

Here, with reference to FIG. 13, the oil absorbing pad attached to the duplex conveying unit will be described.

FIGS. 13A and 13B show the oil absorbing pad housed in the pad holder 218. FIG. 13A is a plan view and FIG. 13B is a side view.

An oil-absorbing pad 2 for absorbing oil is provided on each side of the first setback roller 178 of the double-sided conveying unit 176 (see FIGS. 5 and 6) in the rotation axis direction.
The pad holder 218 in which the 16 is accommodated is fixed. The oil absorbing pad 216 has a rectangular parallelepiped shape,
Pad holder 21 in which oil absorption pad 216 is stored
8 is also a rectangular parallelepiped. However, the pad holder 21
Since the oil absorbing pad 216 is slightly larger than the oil absorbing pad 8, the oil absorbing pad 216 is housed in a state where it is lightly pressed into the pad holder 218. The oil absorbing pad 216 has about one third of its upper surface 216a covered by the upper wall 218a of the pad holder 218, and the remaining two thirds are exposed. Further, both side walls 218b and 218c in the longitudinal direction of the pad holder 218 have a spring property and are urged inward.

The oil absorbing pad 216 is moved to the pad holder 2
13, the oil absorbing pad 216 is obliquely put into the pad holder 218 from the direction of arrow D as shown in FIG. Both side walls 2 of pad holder 218
Even if the oil absorbing pad 216 is strongly inserted by opening the oil absorbing pads 216 outward, the side walls 218b, 218c
Has a spring property urged inward, the side walls 218b and 218c opened outward return to the original position, and the oil absorbing pad 216 is fixed. In this way, the oil absorption pad 216 can be reliably accommodated in the pad holder 218. When removing the oil absorbing pad 216 from the pad holder 218, the oil absorbing pad 216 can be easily removed by opening both side walls 218b and 218c of the pad holder 218 outward.

By the way, although the web oil is applied to the fixing roller from the web in order to clean the fixing roller as is well known, the web oil which cannot be consumed is discharged from the fixing device 164 (see FIG. 5). In the copying machine 10, an oil absorbing pad 216 is placed at a position where the web oil falls, and the web oil is absorbed by the oil absorbing pad 216. Therefore, the inside of the copying machine 10 is not stained by the dripping web oil. Further, since the oil absorbing pad 216 can be easily taken out from the pad holder 218, the workability of replacing the oil absorbing pad 216 is excellent. In the copying machine 10, the oil absorbing pad 216 is replaced in accordance with the replacement of the web. further,
If the double-sided conveyance unit 176 (see FIG. 5) is carelessly lifted, it may collide with the conveyance unit 162 (see FIG. 5). Does not damage the unit 176.

Referring to FIG. 14, a schematic configuration of an electric circuit of copying machine 10 will be described.

FIG. 14 is a block diagram showing an electric circuit of the copying machine 10 shown in FIG.

The electric system of the copying machine 10 includes a DC power supply 22
0, DC controller 300, first motor controller 222, second motor controller 224, fixing heater 2
26, document illumination lamp 132, various motors 110, 22
8, 230, 232, 234, 236, 238, various sensors 240, 242, 244, 246, 248, 25
0, clutches / solenoids 192, 198, 212
(See FIG. 7), the operation unit 14, the high-voltage power supply 252, and the like.

The power from the AC power supply enters through the plug 254, and the circuit breaker 256, the noise filter 25
8. The power is supplied to the power switch 16 through the door switch 260. In this case, when the power switch 16 is ON, the power from the AC power source is supplied to the DC power source 220, the lamp regulator 262, the fixing heater 226, and the fixing sub-heater 2.
64. On the other hand, when the power switch 16 is OFF, the electric power from the AC power supply is supplied to the environmental heater 266.

The DC power supply is DC + 5V, + 12V, +2
It has four types of outputs, 4VR (for control) and + 24VU (for drive), and these outputs are supplied to each unit. The DC power supply includes a power supply cooling fan 268 for cooling. The power supply cooling fan 268 has a rotation lock detection function, and when the locked state is detected, the DC power supply stops all output. Note that when power from the AC power supply is supplied to the DC power supply 220 again, the DC power supply 220 is restored.

Each sensor informs the DC controller 300 of the state of the apparatus, and based on the state, the DC controller 300 controls the driving of each motor and clutches. Further, the high voltage power supply 252, the document illumination lamp 132 and the fixing heater 2
By controlling 26, an image is formed. The operation unit 14 is for performing various settings, displaying status, and the like, and is controlled by the DC controller 300.

Referring to FIG. 15, original illumination lamp 132
Circuits related to the fixing heater system will be described.

FIG. 15 is a block diagram showing circuits related to the original illumination lamp and the fixing heater system.

The power switch 16 is for turning on / off the power of the entire copying machine 10. When the electric application switch OFF signal becomes "L", the built-in relay is turned on and the switch automatically turned off is used as the power switch 16. The document illumination lamp 132 illuminates a copy document, and is supplied with power from a lamp regulator 262. The thermal fuse 270 is
This is to cut off the power supply to the document illumination lamp 132 when the ambient temperature becomes higher than a predetermined temperature due to the heat generated by the document illumination lamp 132. The lamp regulator 262 is supplied with power from an AC power supply, and controls power supply to the document illumination lamp 132 based on a control signal from the DC controller 300. The control signal includes a signal for turning on / off the document illumination lamp 132 and a light amount control signal. When the signal for turning on / off the document illumination lamp 132 is “H”, the document illumination lamp 132 is turned on. The light quantity control signal is an analog signal, and the higher the voltage, the higher the lamp light quantity.

The lamp regulator 262 turns on / off the power supply to the document illumination lamp 132 based on the ON / OFF signal from the DC controller 300. When power is supplied, power corresponding to the light amount control signal is supplied to the document illumination lamp 132. The lamp lighting detection signal (lamp ON detection) is a signal indicating that the lamp is turned on, and becomes “H” when the lamp is turned on. If the ON / OFF signal from the DC controller 300 remains ON for some reason, or if the original illumination lamp 132 remains lit for more than 21 seconds due to a failure of the lamp regulator 262 or the like, the DC controller 30
The gate array 278 above 0 is detected as an abnormal state, and the OFF signal of the power switch 16 is set to “L” to turn off the power switch 16.

Fixing heater 226 and fixing sub-heater 26
Reference numeral 4 denotes a roller for heating the fixing roller 168 (see FIG. 5).
F control is performed. The thermo switch 276 is connected to the fixing roller 16.
8 due to abnormal continuous lighting of the fixing heater 226 and the fixing sub-heater 264, etc.
Becomes open (OFF) state when exceeds the specified value,
The power supply to the fixing heater 226 and the fixing sub-heater 264 is cut off. Thermistor 274 also has a fixing roller 168.
And the temperature of the fixing roller 168 is detected. The SSR 272 turns the fixing heater 226 on according to the fixing device heater ON signal from the DC controller 300.
N / OFF, and the fixing sub-heater 264 is turned ON / OFF according to the fixing device sub-heater ON signal. When the fixing heater 226 is in the ON state, the SSR 272 sets the fixing unit heater ON detection signal to “H” to notify the DC controller 300. Similarly, the fixing sub-heater 264
Is in the ON state, the SSR 272 sets the fixing device sub-heater ON detection signal to “H” to notify the DC controller 300.

On the DC controller 300, the fixing device heater ON detection signal and the fixing device sub-heater ON detection signal are compared with the fixing device heater ON signal and the fixing device sub-heater ON signal, and if the ON signal does not match the ON detection signal. When detected, the gate array 278 detects an abnormal state, and sets the power switch 16 OFF signal to “L” to turn off the power switch 16.

The thermistor 274 detects the temperature of the fixing roller 168 and transmits the temperature of the fixing roller 168 to the DC controller 300. The master CPU on the DC controller 300 controls the fixing device heater ON signal and the fixing device sub-heater ON signal based on the value of the thermistor 274 so that the temperature of the fixing roller 168 becomes a predetermined temperature, and turns ON / OFF these heaters. I do. Further, the comparator 280 sets the fixing unit temperature abnormal signal to “H” when the fixing temperature signal indicates a temperature equal to or higher than a specified temperature, detects the gate array 278 receiving the signal as an abnormal state, and turns off the power switch. The signal is set to “L” to turn off the power switch 16.

Referring to FIG. 16, the control configuration of copier 10 will be described.

FIG. 16 is a block diagram showing a control structure of the copying machine 10. As shown in FIG.

The scanning motor (scanner motor) 230 is
First mirror unit 138 including document illumination lamp 132
5 (hereinafter, referred to as a scanner), and is controlled by the DC controller 300 via the first motor controller 222. A stepping motor is used as the motor, and the driving method is W1
Two-phase excitation, low current drive.

Here, the control will be described in which the scanning motor 230 moves away from the home position, that is, the moving direction at the time of copying is forward, and the moving direction when the scanning motor 230 returns to the home position is reverse.

The rotation speed of the scanning motor 230 is determined based on a scanning motor speed control signal. The scanning motor speed control signal is a clock signal output from the DC controller 300 to the first motor controller 222. The higher the frequency, the higher the rotation speed. The scanner advance speed during the copying operation changes according to the copying magnification. It is slow when enlarging and fast when shrinking. The vertical magnification of copying is changed by changing the speed of the scanner 138. The driving current changes according to acceleration / deceleration, forward constant speed, reverse constant speed, and stop.

A scanner home position sensor 246 is provided as a sensor indicating the home position of the scanner 138. The scanner home position is a position at which the scanner 138 is moved backward by a predetermined distance after the scanner 138 is moved backward and the scanner home position sensor 246 detects the scanner 138. When moving forward, acceleration starts from this position, and when the scanner 138 passes through the scanner home position sensor 246, the scanner 138 is controlled so that the scanner 138 has a constant speed. The scanner home position sensor 246 is also a sensor that indicates the leading edge of the document. When the scanner 138 advances, the document illumination lamp 132 is turned on. The scanner 138 exposes the document while moving forward. When the scanner 138 moves by the size of the document, the document illumination lamp 132 is turned off, and the scanning motor 230 decelerates and temporarily stops. After that, the scanner 138 starts accelerating in the reverse direction, and returns the scanner 138 to the scanner home position while repeating the reverse constant speed and the reverse deceleration.

The lens motor 232 moves a lens for changing the lateral magnification of copying. During the movement of the lens, the DC controller 300 sends a number of drive pulses corresponding to the amount of movement of the lens to the first motor controller 222.
And the driver on the first motor controller 222 drives the lens motor 232 according to the drive pulse.
When the power is turned on, the position of the lens motor 232 is detected by the lens home position sensor 248, and the position of the lens motor 232 is determined by relative position control from that position.

The movement of the lens in the reduction direction is performed by the DC controller 300 outputting the number of pulses corresponding to the movement amount. On the other hand, when the lens is moved in the enlargement direction, N extra drive pulses are issued for the number of pulses corresponding to the amount of movement, and after the movement in the enlargement direction, the extra movement causes N pulses in the reduction direction. The position of the lens is determined by the pulse movement.

As described above, the lateral registration motor 210 is
The horizontal registration sensor 214 and the horizontal registration roller 202 are moved.

The hopper motor 282 is for rotating the screw in the hopper to feed the toner to the developing device 156 (see FIG. 5). When the DC controller 300 detects that there is no toner from the signal of the toner sensor while the main motor 110 is rotating, the DC controller 300 drives the hopper motor 282 to rotate the motor.

The paper discharge reversing motor 284 is a motor for conveying the recording paper having passed through the fixing device 164. As the discharge reversing motor 284, a stepping motor is used, and constant current driving is performed. The driving of the paper ejection reversing motor 284 is performed by the driver of the second motor controller 224 under the control of the DC controller 300. The paper discharge reversing motor 284 rotates so as to discharge the recording paper that has passed through the fixing device to the outside of the apparatus during one-sided copying or the second-sided copying in the duplex mode. When copying the first side of the double-sided mode, as described above, the discharge reverse motor 284 rotates so that the recording paper that has passed through the fixing device 164 is conveyed to the outside of the apparatus, and the trailing edge of the recording paper is moved. When reaching a predetermined position upstream of the second discharge roller 172, the discharge reverse motor 284 temporarily stops. After that, the paper discharge reversing motor 284 rotates in the reverse direction, whereby the recording paper is conveyed toward the both-side conveyance unit in the apparatus. At that time, the drive current is set higher than in the paper discharge direction,
When the recording paper is fed horizontally, the discharge reversing motor 284 is rotated at twice the speed in the discharge direction. When the recording paper is longer than a predetermined value (300 mm or more in the embodiment), the speed is the same as the speed in the discharge direction. The discharge reverse motor 284 is rotated at the speed.

As described above, the setback motor 18
Numeral 8 is for loading the recording paper on which copying of the first side has been completed into the double-sided transport unit, or for transporting the loaded recording paper when re-feeding.

The blank shutter motor 236 moves a shutter for determining a blank area of a recording sheet. The home position of the shutter is detected by the blank shutter home position sensor. Under the control of the DC controller 300, the driver of the second motor controller 224 drives the blank shutter motor 236 so that the blank shutter moves from the home position according to the recording paper size.

The cleaner motor 238 is for moving a cleaner pad for cleaning the wire for transfer charging. The position of the cleaner pad is detected by a wire cleaner detection switch disposed in front of and behind the wire, and the DC motor 300 controls the cleaner motor based on this detection.

The main motor 110 is a DC brushless motor with a controller, and serves as a driving source for a drum unit, a developing device, and a paper transport system of the copying machine 10. The main motor 110 is turned ON / OFF from the DC controller 300.
It is controlled by the OFF signal.

The lifter motor 228 is connected to the cassettes 18 and 2.
0 (see FIG. 1) to feed the recording paper
12 and is controlled by the DC controller 300. When the cassette size sensor detects that the cassettes 18 and 20 have been inserted, the DC controller 300 controls and drives the lifter motor 228 until the lifter sensor 224 detects that the cassette 18 or 20 is inserted, and the lifter motor 228 rotates to lift up. The lift-up state is released by a mechanical mechanism at the time of pulling out the cassette.

As for the heater and the SSR 272, FIG.
As described in Section 5.

A high-voltage power supply (HVT) 252 outputs high voltages for primary, development, transfer, and separation during image formation.
The DC controller 300 controls the recording paper conveyance and the driving of the scanning motor 230 in synchronization with the timing.

The main body fan 290 is composed of two axial fans, two of which are driven simultaneously. It rotates at full speed during copying and at half speed after a certain period of time after copying is completed. The main body fan 290 has a function of discharging heat and a function of discharging air containing ozone generated by corona discharge on the drum through an ozone filter and then out of the machine.

The operation unit 14 has several keys, display LEDs, and 7-segment LEDs, as described above. Also,
The operation unit 14 has a function of setting a copy mode and the number of copies, and also has a key for starting a copy.
The DC controller 300 determines a mode or the like set by a key of the operation unit by operating the key, and recognizes a copy operation. In accordance with the recognized copy mode, the operation unit displays the setting mode using the display function LED and the 7-segment LED. When detecting that the copy start key is pressed, the DC controller 300 controls the copying machine to perform a copy operation in accordance with the set copy mode.

With reference to FIGS. 17 to 20, a description will be given of a transport unit (transport device) that transports the recording paper onto which the developed image has been transferred to the fixing device.

FIG. 17 is a schematic diagram showing a transport unit of a copying machine, and FIG. 18 is a schematic diagram showing two belts and a transport auxiliary member. 19A and 19B show a conveyance auxiliary member and two belts, FIG. 19A is a side view showing only the conveyance auxiliary member, and FIG. 19B shows a positional relationship between the two belts and the conveyance auxiliary member on the downstream side in the recording paper conveyance direction. FIG. 3C is a schematic diagram viewed from the transport direction, and FIG. 3C is a schematic diagram illustrating the positional relationship between the two belts and the transport auxiliary member on the upstream side in the recording paper transport direction when viewed from the transport direction. FIG.
FIG. 4 is a schematic diagram showing a state in which a recording sheet of a minimum size among recording sheets used in a copying machine is being conveyed. In these drawings, the same components as those in FIG. 5 are denoted by the same reference numerals.

As described above, the recording paper on which the developed image has been transferred is separated by the static elimination needle or the like and guided to the transport unit.

The transport section includes a driving roller 292, driven rollers 294, 298, and these two rollers 292, 294.
A sheet metal frame 296 having an upper surface in contact with the back surface of the belt 296 and constituting a frame of the transport unit is provided. The drive roller 292 is rotated by the main motor 110. Below the sheet metal frame 296 (inside the transport unit), a suction fan 302 for sucking recording paper is arranged. The suction fan 302 sucks air from above and discharges the air to the back side beside the suction fan. A large number of holes 296a are entirely formed on the upper surface of the sheet metal frame 296 for air suction. Drive roller 2
92 and the driven rollers 294, 298 have two belts 30.
The two belts 304 rotate while contacting the upper surface of the sheet metal frame 296 with the rotation of the drive roller 292. The surface of the belt portion in contact with the sheet metal frame 296 is about 2.5 mm larger than the surface of the sheet metal above it.
It is at a position that is high enough (the belt thickness is approximately 2.5 mm). The two belts 304 are also provided with a large number of holes 304a for air suction. In addition, sheet metal frame 2
An insulating conveyance auxiliary member 306 extending in the recording paper conveyance direction is fixed between the two belts 304 on the surface of the recording medium 96.

As shown in FIG. 19A, the conveyance assisting member 306 extends in the recording paper conveyance direction (the direction of arrow B).
A portion 308 on the downstream side in the recording paper transport direction (downstream portion) 308 from the central portion in the longitudinal direction is located higher than a portion 310 on the upstream side in the recording paper transport direction (upstream portion) 310 from the central portion. Upper surface 30 of downstream portion 308 of transport assist member 306
8a shows two belts 30 as shown in FIG.
4 is located at the same height as the upper surface 304a. On the other hand, as shown in FIG. 19C, the upper surface 310a of the upstream portion 310 of the transport assisting member 306 is the upper surface 3 of the two belts 304.
04a.

As shown in FIG. 17, the recording paper conveyed to the recording paper conveyance section is conveyed to the fixing roll 168 while being in close contact with the two belts 304 by the suction fan.
At the time of this conveyance, as described above, the conveyance assist member 306 is located upstream of the center of the sheet metal frame 296 in the recording paper conveyance direction.
Is located at a position lower than the upper surfaces of the two belts 304, the portion of the recording paper between the two belts 304 is the upper surface 304 of the belt 304.
Even if it undulates below a, it does not contact the sheet metal frame 296. Therefore, friction does not occur due to the contact between the recording paper and the sheet metal frame 296, and a decrease in the conveying force due to the friction can be prevented.

On the other hand, on the downstream side of the center portion of the frame sheet metal 296 in the recording paper conveyance direction, as described above,
06 is located at the same height as the upper surface 304a of the two belts 304, the portion of the recording paper between the two belts 304 is the portion that is in close contact with the belt 304. And the same height as Therefore, the recording paper is flattened by eliminating the waving, and is conveyed to the fixing roll 168 while being flat. For this reason, in the fixing device, wrinkles due to waving do not occur on the recording paper.

In the above example, the upper surface 308a of the downstream portion 308 of the transport auxiliary member 306 and the upper surface 304a of the two belts 304 are at the same height.
May be configured so that the position of the upper surface 308a of the downstream portion 308 is higher than the position of the upper surface 304a of the two belts 304 by about 0.3 mm. Also, the upper sheet metal 296
A transport auxiliary member 306 extending in the recording paper transport direction
Are formed, at least the transport assisting member 306 formed between the two belts 304 is formed in the above-described shape. In the above example, the transport assisting member 306
Although the position at which the height has been changed is substantially the center in the transport direction, it may be as shown in FIG.

In the conveyance assisting member 306 shown in FIG. 20, when the leading end of the recording paper 312 of the smallest size among the recording papers used in the copying machine 10 is nipped by the fixing roller 168,
At the position where the rear end of the recording paper 312 of the minimum size is located, the position of the upper surface of the transport assisting member 306 is raised. For this reason, until the leading edge of the recording paper of all sizes used in the copying machine 10 is nipped by the fixing roller 168, the rear end of the recording paper is located at the upstream portion 310 of the transport assisting member 306. .

When comparing the transporting force between the upstream portion 310 and the downstream portion of the transport assisting member 306, the upper surface 308a of the downstream portion 308 is positioned on the two belts 3.
Since the upper surface 304 a is almost the same height or slightly higher than the position of the upper surface 304 a, the upper surface 308 a comes into contact with the recording paper 312, and the conveyance is slightly lower than in the upstream portion 310. However, at least the rear end of the recording paper 312 is being conveyed through the upstream portion 310 of the conveyance assisting member 306 until the front end of the recording paper 312 is nipped by the fixing roller 168. Even if the sheet is conveyed on the downstream side portion 308 of the conveyance auxiliary member 306, the conveyance force hardly decreases. By the time the rear end of the recording paper 312 reaches the downstream portion 308 of the transport assisting member 306, the leading end of the recording paper is nipped by the fixing roller 168 and transported.
Therefore, even if the rear end of the recording paper 312 is conveyed through the downstream portion 308 of the conveyance assisting member 306 having a slightly lower conveyance force, the fixing roller 168 also conveys the recording paper 312. 312 is satisfactorily conveyed.

Referring to FIGS. 21 and 22, the fixing device of copying machine 10 will be described.

FIG. 21 is a schematic diagram showing the structure of the fixing device, and FIG. 22 is a timing chart showing the temperature adjustment of the fixing device. In these drawings, the same components as those in FIGS. 1 to 19 are denoted by the same reference numerals.

The fixing device 164 melts and presses the transferred image transferred on the recording paper to fix it on the recording paper. For this purpose, the fixing device 164 is provided with a fixing roller 168 in which an iron or aluminum core is coated with a fluororesin having excellent releasability and heat resistance, and the recording paper is conveyed while being nipped between the fixing roller 168 and the fixing roller 168. And a pressurizing roller 169 to be provided. The pressure roller 169 presses the fixing roller 168 with a total pressure of 10 to 30 kg to hold the recording paper therebetween, and is made of an elastic material such as silicon rubber or fluorine rubber. Further, the fixing device 164
A fixing heater 226 and a fixing sub-heater 264 for heating the fixing roller 168 are provided. Fixing device 164
Further comprises a thermistor 274 for detecting the surface temperature of the fixing roller 168 by contacting the surface of the fixing roller 168;
A thermoswitch 276 for detecting an abnormal temperature of the fixing roller 168 and cutting off the power supply to the heater. Further, in order to clean the fixing roller 168, a web 314 for cleaning the surface of the fixing roller 168 by impregnating a non-woven fabric or the like with silicone oil,
A web feed roller 316 that feeds the web 14 to the fixing roller 168; a web pressure roller 318 that presses the web 314 against the fixing roller 168; and a web guide plate 320 that increases the contact area of the web 314 with the fixing roller 168 and improves the cleaning effect. And a web take-up roller 322 that collects the web 314 after cleaning.
These are components of the fixing device 164. An entrance guide plate 324 that guides the recording paper to a fixing nip formed by the fixing roller 168 and the pressure roller 169 is disposed in front of the fixing device 164 (upstream in the recording paper conveyance direction). Further, on the rear side (downstream side in the recording paper transport direction) of the fixing device 164, a first paper ejection roller 170 and a second paper ejection roller 172 for sending the fixed recording paper to a discharge unit.
Is arranged.

A control system of the fixing device 164 will be described.

First, a method of controlling the temperature of the fixing device 164 will be described.

In the fixing device 164, the fixing roller 168 is heated by two halogen heaters (fixing heater 226 and fixing sub-heater 264) having different heat distributions, and the surface temperature is detected by the thermistor 274. The two heaters are a fixing heater 226 having a heat distribution at the height of the center.
And a fixing sub-heater 264 having a heat distribution at the edge height. The ratio of the lighting time of these two heaters is changed in accordance with the width of the recording paper to be copied, thereby making the surface temperature distribution of the fixing roller 168 uniform and the fixing roller 168 by continuous copying of small size paper. Prevents end heating.

The thermistor 274 detects the surface temperature of the fixing roller 168, and inputs the thermistor resistance value (TH1) to the DC controller 300. DC controller 300
Indicates a fixing temperature based on the thermistor resistance value (TH1), and a fixing heater 226 drive signal (MHRD) for driving the fixing heater 226 and a drive fixing sub-heater 264 drive signal (SHRD) for driving the fixing sub-heater 264. To the SSR 272. Based on these fixing heater drive signals (MHRD, SHRD), the SSR
Reference numeral 272 controls ON / OFF of a switch for supplying AC power to the two fixing heaters.

Next, the protection function of the fixing device 164 will be described.

In the fixing device 164, malfunction of the fixing heater is prevented by the following three methods.

(1) Protection by the Signal of Thermistor 274 The DC controller 300 monitors the voltage of the thermistor 274, converts it into temperature, and detects an error, displays an error message on the operation unit 14 (see FIG. 1) and copies it. The operation of the machine 10 is stopped. That is, when the temperature exceeds a predetermined abnormal temperature, a power-off signal (PWOFF) is output by the hardware circuit to turn off the power switch. If the thermistor value does not change even though the fixing heater is turned on, the fixing heater is turned off and an error message is displayed.

(2) Protection by Signal from SSR 272 When the SSR 272 is short-circuited and the fixing heater continues to be turned on, the power-off signal (P
WOFF) and the power switch is turned off. The fixing heater driving SSR 272 outputs an SSR drive detection signal (MSSRD, SSSRD) to the DC controller 300 when the SSR 272 is ON. The DC controller 300 receives the heater drive signals (MHRD, SHRD) and SS
The R drive detection signals (MSSRD, SSSRD) are monitored at the same time.
When the R drive signal is ON, it is determined that there is an abnormality.

(3) Protection by Thermoswitch 276 When the temperature detected inside the thermoswitch 276 reaches a predetermined abnormal temperature, the thermoswitch 276 is turned off and the power supply to the fixing heater is cut off.

[0146] These protection operations are stored in the memory and are not released by normal power-off / on operations, but are released only by a special release operation by a service person or the like.

Next, the drive control of the fixing web 314 will be described.

The web 314 for cleaning the fixing roller 168 is activated by turning on / off the web drive solenoid 326 based on a web drive signal (CBSD) output from the DC controller 300. When the web drive solenoid 326 is turned ON once, the web take-up roller 322 rotates to wind up the web 314 so that the web 314 is fed by about 40 μm. The number of operations of the web drive solenoid 326 per sheet of recording paper is set to a predetermined value for each size of recording paper. When the total operation of the web drive solenoid 326 reaches a predetermined number, a message for replacing the fixing web 314 is displayed on the operation panel. Note that a positive bias of about 1 kV is applied to the fixing roller 168 during the passage of the recording paper, so that the adhesion of the toner to the fixing roller 168 is reduced.

Referring to FIG. 22, a method of adjusting the temperature of fixing device 164 will be described.

When the power switch is turned on, the fixing heater 226 and the fixing sub-heater 264 are continuously turned on, and the fixing roller 168 is detected based on the temperature detected by the thermistor 274.
Is heated to a target temperature (for example, 175 ° C.) (warm-up, WMUP). When the surface temperature of the fixing roller 168 reaches 175 ° C., the main motor 110 is driven, a warm-up rotation (WMUPR) is performed for 5 seconds, and the temperatures of the fixing roller 168 and the pressure roller 169 are made uniform. Thereafter, when the surface temperature of the fixing roller 168 reaches 190 ° C., the standby state (STBY) is established, and the system waits for the copy key to be turned on. In this standby state, the surface temperature of the fixing roller 168 is kept constant while controlling the blinking of the fixing heater. In this standby state, the copy key is
If N, recording paper is fed and copying is performed.

The fixing device 164 controls the target temperature to be lowered based on the number of copies, and the fixing heater 226 and the fixing sub-heater 264 based on the width of the recording paper, in order to prevent the end portion from being heated due to continuous feeding of the small-sized paper. A method of controlling the ratio of the lighting time is adopted. For example, as shown in the drawing, the target temperature of 190 ° C. is controlled to be constant for recording paper of A3 size, A4 size, and 11 inch × 17 inch size paper width. However, in the case of recording paper having a paper width such as A4R size, 185 sheets are required to be printed from the 40th sheet to the 89th sheet.
℃ is controlled. The temperature is controlled to be lowered to 180 ° C. after the 89th sheet. On the other hand, for recording paper having a paper width of B4 size, B5 size, B5R size or the like, the temperature is controlled to be lowered to 180 ° C. after the 40th sheet. Furthermore, B5R size or smaller (le
ss), the recording paper with a paper width of 200
The temperature is controlled to 175 ° C. until the first sheet, and is controlled to 170 ° C. after the 200th sheet. Also,
As the width of the recording paper is smaller, the lighting time of the fixing heater 226 having the heat distribution at the center height is controlled to be longer than the lighting time of the fixing sub-heater 264 having the heat distribution at the edge height, and the edge rising is controlled. Temperature is prevented. In the figure, SCFW
Means the advance of the optical system, the original is illuminated by the original illumination lamp, and the reflected light exposes the photosensitive drum via the mirror and the lens. SCRV means backward movement of the optical system, and the optical system returns to the home position in preparation for the next copy. LSTR means rotation of the photosensitive drum for electrostatically cleaning the surface of the photosensitive drum.

Referring to FIGS. 23, 24, 25, and 26, the structure of the paper discharge unit and the control of its driving will be described.

FIG. 23 is a perspective view schematically showing a schematic structure of a paper discharge section, and FIG. 24 is a schematic view showing conveyance of a recording sheet. FIG. 25 is a schematic diagram showing transmission of mechanical drive of each motor and each roller.

In the copying machine 10, a discharge reversal operation is performed in order to automatically perform double-sided copying. First and second paper discharge rollers 170 and 172 are disposed in the paper discharge unit. The first paper discharge roller 170 is driven by the main motor 110, and the second paper discharge roller 172 is driven by the paper discharge motor 184. Is done. First and second discharge rollers 170 and 172
The transport path between the two is a transparent back-feed prevention sheet (Mylar) 1
The back-feed prevention sheet 182 prevents the recording paper from being conveyed to the fixing device 164 again, as described below. Immediately after the first paper discharge roller 170, a paper discharge sensor for detecting recording paper is arranged. The signal obtained by the paper ejection sensor is used to calculate the timing at which the trailing edge of the recording paper passes through the fixing roller and the timing at which the trailing edge of the recording paper reaches approximately 10 mm before the second paper ejection roller 172. , And is used to determine whether the recording paper is being conveyed normally.

The recording paper 328 that has exited from the fixing device 164 and has advanced in the direction of arrow E is conveyed to the first paper discharge roller 170 as shown in FIG.
And reaches the second discharge roller 172. The second paper discharge roller 172 conveys the recording paper 328 in the paper discharge direction (the direction opposite to the direction of arrow F), but discharges the paper at a predetermined timing when the rear end of the recording paper 328 passes through the reverse feed prevention sheet 182. The motor 184 stops once. Thereafter, the paper discharge motor 184 starts to rotate in a direction opposite to the conventional direction. As a result, the recording paper starts to be conveyed in the direction of arrow F, and the rear end of the recording paper is conveyed as the leading end of the recording paper. FIG.
As shown in (b), the new leading end abuts against the reverse feed prevention sheet 182. As a result, as shown in FIG. 24C, the recording paper is conveyed downward by being guided by the back-feed prevention sheet 182 and the pair of guide plates. The following description will be described later.

FIG. 26 is a block diagram showing a control circuit for controlling the discharge motor 184.

As the paper discharge motor 184, a two-phase stepping motor is used. The discharge motor 184 is disposed very close to the fixing device 164, and is easily affected by the temperature of the fixing device 164 and the like. There is a possibility that the torque of the discharge motor 184 is reduced due to the influence of this temperature, and the discharge motor 184 does not function. Therefore, the discharge motor 184 is controlled at a constant current.

5 output from DC controller 300
Types of signals (DMCLK, DMRON, DM
D, DMI1, DMI2) are output by a motor drive circuit and a discharge motor drive circuit in the board of the second motor controller 224 (see FIG. 12) to a discharge motor drive pulse signal (DMA,
DMA *, DMB, DMB *). The rotation direction and rotation speed of the discharge motor 184 are controlled based on the drive pulse signal.

The ON / OFF control of the discharge motor 184
It is controlled by a discharge motor drive signal (DMRON). When the DMRON signal becomes "0", a pulse signal is output from the motor drive circuit, and the pulse signal is input to the discharge motor drive circuit, where the discharge motor drive pulse signal is output and the discharge motor 184 rotates.

The output sequence of the drive pulse signal can be changed according to the discharge motor rotation signal (DMD). Thus, the rotation direction of the paper discharge motor 184 is controlled. DMD
Is "1", the discharge motor 184 rotates in the direction of reversing the recording paper (the direction of the arrow in FIG. 23).

The paper discharge motor 184 clock signal (DMCL
K) controls the rotation speed of the discharge motor 184. In the copying machine 10, the rotation speed of the paper discharge motor 184 is controlled according to the paper discharge / reversal and the length of the recording paper. For example, the rotation speed of the discharge motor 184 is set to 18
0 mm / sec. The rotation speed of the paper discharge motor 184 at the time of reversing is set to 360 mm / sec when the length of the recording paper in the conveyance direction is 300 mm or less, and the rotation speed in the conveyance direction is set to 300 mm.
When it exceeded 180 mm / sec.

When the rotation speed of the discharge motor 184 is switched as described above, the magnitude of the drive current is also changed.
The magnitude of the drive current is switched by the discharge motor 184 current control signal (DNI1, DMI2). At the time of the paper ejection operation, the DC controller outputs a DNI1 signal to the paper ejection motor drive circuit on the motor controller board,
On the other hand, at the time of reversal, the DC controller 300 outputs a DMI2 signal to the paper discharge motor drive circuit. When the DMI2 signal is input to the discharge motor drive circuit, the discharge motor drive circuit increases the magnitude of the output drive current. The reason is that at the time of reversal, the recording paper discharged from the discharge unit is drawn back into the copying machine, so that a larger load is applied to the paper discharge motor 184 than at the time of paper discharge. This is because it is desired to increase the driving torque of the motor.

Referring to FIGS. 27 to 38, the operation of forming an image on the first side of the recording paper and then transporting the recording paper from the paper discharge unit to the duplex transport unit (lower transport unit) and loading it (setback) Operation) and the process until a plurality of recording papers stacked in the lower transport unit are transported to the registration rollers will be described.

FIG. 27 is a schematic diagram showing a state in which the leading end of the recording paper is abutted against the stopped first setback roller to form a loop of the recording paper. FIG. 28 is a schematic diagram showing a state where the first and second setback rollers have started to rotate at the same time as lowering the lower transport flapper. FIG. 29 is a schematic diagram showing a state in which the leading end of the recording paper is located at a distance 1 from the first setback roller toward the exit side. FIG. 30 is a schematic diagram illustrating a state where the second recording sheet has been sent to the lower transport unit. FIG. 31 is a schematic diagram illustrating a state in which the leading end of the second recording sheet is abutted against the stopped first setback roller to form a loop of the second recording sheet. FIG. 32 is a schematic diagram showing a state in which the lower conveyance flapper is lowered and the first and second setback rollers are started to rotate at the same time. FIG.
FIG. 5 is a schematic diagram showing a state in which the leading end of the second recording sheet is protruded from the first setback roller toward the exit side by a distance 1 and receives the third recording sheet. FIG. 34 is a schematic diagram showing a state in which the stacked recording paper is advanced and the first recording paper is detected by the lower conveyance exit sensor. FIG. 35 is a schematic diagram illustrating a state in which the first recording sheet has come out of the lower conveyance exit sensor. FIG. 36 is a schematic diagram illustrating a state where the lower conveyance exit sensor detects the leading end of the first recording sheet. FIG. 37 is a schematic diagram showing a state in which the lower conveyance flapper is lowered and the first and second setback rollers are temporarily stopped. FIG.
FIG. 4 is a schematic diagram showing a state where the first recording paper and the second and subsequent recording papers are separated. FIG. 39 is a schematic diagram showing a state where the first recording sheet has passed through the second setback roller. FIG. 40 is a schematic diagram illustrating a state in which the refeeding operation of the second recording sheet has been started.

The recording paper on which the image has been formed on the first side is transferred to the double-sided conveyance unit 1 disposed above the cassettes 18 and 20.
76, and then conveyed again to the transfer area 128 to form an image on the second side. As described above, the two-sided conveyance unit 176 includes, in order from the upstream side in the conveyance direction, a lower conveyance sensor 190 for detecting the rear end of the recording paper, a first setback roller 178 for nipping and conveying the recording paper,
Second setback roller 18 for nipping and transporting recording paper
0, a flapper 194 for preventing unnecessary conveyance of the recording paper, a lower conveyance exit roller 200 for taking out the recording paper from the duplex conveyance unit 176, and the like.

The first sheet of recording paper is sent from the sheet discharge section to the double-sided conveyance unit 176 via the lower conveyance entrance roller 186 after the copy of the first side is completed. As a result, as shown in FIG. 27, the leading end of the recording sheet abuts against the first setback roller 178 that is stopped to form a loop of the recording sheet 330,
Correct skew. From this state, when the first and second setback rollers 178 and 180 are started to rotate and the recording paper is started to be fed to the right side of the drawing, the first and second setback rollers 178 and 180 are also moved to the right of the drawing. Start spinning to feed. When the recording paper is conveyed to the right side of the drawing for a predetermined time after the lower conveyance sensor 190 detects the rear end of the recording paper, the rear end of the recording paper passes through the lower conveyance sensor 190 and the recording paper moves to the duplex conveyance unit 176. end. Since the case of single copy has been described above, the case of multiple copies will now be described.

When the trailing edge of the recording paper passes through the lower transport sensor 190, if the leading edge of the recording paper is detected by the setback sensor 196 and it is determined that the recording paper reaches the flapper 194,
The flapper 194 is operated, and the recording paper is conveyed by the flapper 194 in a scooping direction. On the other hand, as shown in FIG. 28, when the leading end of the recording paper does not reach the flapper 194,
These operations become unnecessary. In this state, the first and second
The setback rollers 178 and 180 are temporarily stopped, and the first
Then, the second setback rollers 178 and 180 are reversed, and the first and second setback rollers 178 and 180 are rotated at a position where the leading edge of the recording paper is a distance 1 (for example, 8 mm) from the first setback roller 178 toward the outlet side as shown in FIG. Setback rollers 178, 18
Stop 0 and stop the recording paper. In this state, the apparatus waits until the second recording sheet 332 is conveyed. As shown in FIG. 30, the second recording paper 332 is
It is sent to 76. As shown in FIG. 31, similarly to the first recording paper 330, the second recording paper 332 abuts on the stopped first setback roller 178, and the second recording paper 332 contacts the second recording paper 332. 332 loops through the first sheet of recording paper 3
Formed on 30 to correct skew. From this state,
The operations similar to those in FIGS. 28 and 29 are repeated, and a plurality of recording sheets are stacked with a predetermined interval (here, 8 mm) shifted. FIG. 32 shows a state where two recording papers are stacked. FIG. 33 shows a state in which two stacked recording papers 330 and 332 receive a third recording paper.

From the state shown in FIG. 31, until the two recording papers 330 and 332 stacked pass the lower end of the lower conveyance sensor 190, the two recording papers 330 and 332 are stacked in the same manner as described above. Is transported. Thereafter, the leading ends of the two recording papers 330 and 332 are further set to the setback sensor 19.
No. 6, the two recording papers 330 and 332 are conveyed. As shown in FIG. 34, two recording papers 330, 3
When the setback sensor 196 detects the tip of the setback roller 32, the first and second setback rollers 178 and 180 are stopped. Next, the first and second setback rollers 17
8 and 180, the leading edge of the second recording paper 332 is moved a predetermined distance (for example, 5 m) from the setback sensor 196.
m) Return, as shown in FIG. 35, when the leading edge of the recording paper 332 reaches this position, the first and second setback rollers 178 and 180 are stopped. When the trailing edge of the recording paper has passed the lower conveyance sensor 190 in the state shown in FIG. 32 and the leading edge of the recording paper has already passed the setback sensor 196, the above-described operation shown in FIG. 34 is not performed. , The operation shown in FIG. 35 is performed.

Referring to FIG. 36 to FIG. 38, the recording paper having an image formed on one side is transferred to the double-sided conveyance unit by 17
The refeeding operation after the operator exchanges the original and presses the copy start key from the state of being accommodated in the paper feeder 6 will be described.

When the copy start key is pressed, the first and second setback rollers 178 and 180 start to rotate, and as shown in FIG. Transport to The transport speed at this time is lower than the previous transport speed, for example,
About half the speed. After the recording paper 330 is detected by the setback sensor 196, the recording paper 330 is further conveyed at this conveying speed by a predetermined amount and the first and second setback rollers 17 are moved.
Stop 8,180. Simultaneously with this stop, the lower transport flapper 194 is lowered as shown in FIG. The recording paper 3 is positioned such that the leading end of the lower transport flapper 194 contacts the center of the difference between the leading end of the lower recording paper 330 and the leading end of the upper recording paper 332.
30, 332 are being conveyed. The reason for the deceleration described above is to improve the accuracy from the timing when the recording paper 330 is detected by the setback sensor 196 to the stop.

At the same time that the lower transport flapper 194 is lowered,
Again, the first and second setback rollers 178, 180
Start rotating. In this case, it is rotated at a normal speed. As a result, as shown in FIG.
0 is conveyed toward the re-feed roller 200, the upper recording paper 332 is conveyed along the upper surface of the lower conveyance flapper 194, and the two recording papers 330 and 332 are separated. At this time, the re-feed roller 200 also starts rotating. The flapper solenoid turns off when the recording papers 330 and 332 are separated.
F. Here, it is turned off in 0.5 seconds.

With reference to FIGS. 39 and 40, a description will be given of a process from when the sheet is re-fed to when the recording sheet reaches the registration roller 122. FIG. It should be noted that after the re-feeding, the recording paper is
, The horizontal registration roller 202 described above operates.

The lower recording paper 330 is conveyed to the horizontal registration roller 202 by the re-feed roller 200. This recording paper 3
When the 30 abuts on the lateral registration roller 202, a loop is formed as described above. When the loop amount reaches a predetermined amount (here, the amount of recording paper fed by adding 10 mm to the distance between the re-feed roller 200 and the horizontal registration roller 202), the horizontal registration roller 202 starts rotating. The detection of the predetermined amount can be easily calculated based on the transport speed and time of the recording sheet from the time when the lateral registration sensor 206 detects the leading end of the recording sheet 330.

When the trailing edge of the recording paper 330 has passed the second setback roller 180, the first and second setback rollers 178 and 180 start to reverse, and as shown in FIG. Transport in the direction. Recording paper 33
2 has the setback sensor 19 as described above.
When reaching a predetermined position (about 5 mm) upstream from 6, the first and second setback rollers 178, 180 stop.
This is to accommodate the next copy.

The horizontal registration rollers 202 convey the recording paper 330 toward the registration rollers 122 as shown in FIG. At the same time as this conveyance, as described above, the horizontal registration roller 202 moves in the horizontal direction (the direction orthogonal to the recording paper conveyance direction) to adjust the position of the recording paper. As described above, a loop is formed with the recording paper 330 abutting on the registration roller 220, and the timing to convey the recording paper 330 to the transfer area is waited.

Lastly, a description will be given of the blank shutter unit and the variable power function of the optical system of the copying machine 10. The connection relationship between the configuration of the blank shutter unit and the electric control will be described with reference to FIGS.

FIG. 41 is a perspective view showing a schematic configuration of a blank shutter unit, and FIG. 42 is a schematic view showing a state where a photosensitive drum is subjected to blank exposure.

The blank exposure means that the photosensitive drum 126 is exposed to form an area where no image is formed on the recording paper. In the copying machine 10, the light of the pre-exposure lamp 334 is The blank exposure is performed by irradiating the entire surface with the blank reflecting plate 338, respectively. The blank exposure area includes one open / close shutter 340 and two slide shutters 342 and 34.
4.

The open / close shutter 340 is disposed on the optical path where blanking is performed on the entire surface, and is opened / closed by a blank shutter solenoid (not shown). Blank shutter solenoid is ON for margins at the leading and trailing edges of recording paper
It is formed by opening.

Two slide shutters 342 and 344
Are arranged on the optical path where the size blanking is performed, and slide in the axial direction of the photosensitive drum 126 simultaneously by the forward / reverse rotation of the blank shutter motor (M8) 346. In accordance with the slide amount, the amount of blank space formed on the left and right sides of the recording paper is controlled, and the black-out area of the non-image forming area such as during reduction copying is controlled. When the power is ON, the two slide shutters 342 and 344 are temporarily returned to the home position by the blank shutter motor 346. From the position of this home position, reduction ratio,
The blank shutter motor 346 receives a drive pulse from the DC controller 300 and rotates according to the recording paper size and the copy mode, and the slide shutters 342 and 34 are rotated.
4 slides to a predetermined position. Slide shutter 3
When 42 moves in the direction of arrow G and slide shutter 344 moves in the direction of arrow H, both ends of the optical path on which the size blanking is performed on the surface of the photosensitive drum become large, and the potential at both ends disappears. As a result, images cannot be formed at both end portions, and the recording paper is blank. When the blank shutter motor 346 rotates in the opposite direction, the opposite occurs.

Referring to FIGS. 43 to 47, the scaling function of copying machine 10 will be described.

FIG. 43 is a perspective view showing a schematic configuration of the lens driving system shown in FIG. 5, and FIG. 44 is a plan view of the lens driving system shown in FIG. FIG. 45 is a plan view showing in detail a fixing plate of the lens driving system of FIG. 43, and FIG.
It is a top view which shows the modification of the fixing plate of No. 5 in detail. Also,
FIG. 47 shows the eccentric pin, (a) is a front view, (b) is a side view, and (c) is a bottom view.

The lens 350 enlarges or reduces an image recorded on a document and projects light carrying an image signal on an image carrier. Therefore, the lens 350 is connected to the rail 352.
, And move freely in the directions of arrows I and J. To enlarge the original image on the recording paper, the lens 350 is moved in the direction of arrow I. When the original image is reduced and formed on recording paper, the lens is moved in the direction of arrow J. A driving source for moving the lens 32 in the arrow I direction or the arrow J direction is a stepping motor 356. This stepping motor 356 is connected via a first motor drive board 358 to
It is controlled by the DC controller 300. The moving end in the direction of arrow I is the home position of the lens 350,
At this home position, a home position sensor 360 for detecting the lens 350 is arranged.

The gear 362 is fixed to the motor shaft of the stepping motor 356. DC controller 3
00 and the stepping motor 356 rotates, the belt 3 wound around the gear 362 is rotated.
The lens 350 fixed to the belt 368 moves via the integrated pulley gear 366 and the belt 368. Thereby, it can be moved corresponding to each percentage at the time of zooming.

Each of both ends in the longitudinal direction of the rail 352 is fixed independently of each other. The rail end in the direction in which the lens moves when the document image is reduced (the direction of the arrow J) is fixed to a plate-like fixing base 372 (hereinafter, fixing plate 372) with screws 370. A pulley gear 374 for a belt is rotatably fixed to the fixing plate 372. On the other hand, the rail end in the direction in which the lens moves when the original image is enlarged (the direction of the arrow I) is a plate-like fixed base 37.
6 (hereinafter, fixed plate 376). The fixing plate 376 is configured to be movable in the directions of arrows I and J so as to obtain the tension of the belt 368, and the pulley gear 366 is rotatably fixed. These fixing plates 372 and 376 are fixed to the lens base 378.

The above-described lens moving stepping motor 356 is fixed to the fixed plate 376 via the motor mounting plate 378 in the vicinity of the rail support portion or the rail end. The motor mounting plate 378 is fixed to the fixing plate 376 so as to be rotatable about the fulcrum 378a in the direction indicated by the arrow K. A tension pulley 380 that contacts the belt 364 is rotatably fixed to the motor mounting plate 378. Accordingly, the tension of the belt 364 can be set to a desired value by rotating the motor mounting plate 378 and changing the pressing force with which the tension pulley 380 presses the belt 364.

In order to project a good image signal on the photosensitive drum 126 (see FIG. 5), it is necessary to adjust some components of the lens drive system. Among the adjustment items, there is an adjustment in the asynchronous direction. For this adjustment, the fixing plate 372 has round holes 382 and 384 formed therein.
6, round holes 386 and 388 are formed. Embosses 390 that fit into these round holes are formed on the lens mount 378. This emboss 390 is inserted into a round slot 382,
384, 386, and 388, the rail 352 is moved in a small amount (± 0.7
(About 5 mm or less).

As a result of configuring the lens system 146 as described above, the fixing plates 372 and 376 can be independently moved in the asynchronous direction of the lens 350.

The fixing plates 372 and 376 are formed with seven horizontally long holes 392 and 394, respectively. Round holes corresponding to these horizontally long holes 392 and 394 are formed in the lens mount 378. When assembling the components to the lens base 378, pins that fit into the horizontally long holes 392a and 394a are inserted to fix the fixing plates 372 and 376 to a desired design position. After this assembly, there may be a case where adjustment in the asynchronous direction is required during the adjustment process in the image forming apparatus main body. In this case, the rail 352 is moved in the direction of the arrow K so as to be within the adjustment standard. At the time of this movement, six circular long holes 3 other than the horizontal circular long holes 392a and 394a
By adjusting the positions of the holes 92 and 394 and the round holes, the fixing plates 372 and 376 can be moved in three directions in the direction of arrow K.

Referring to FIGS. 46 and 47, a modification of the fixing plate will be described.

In these figures, the same components as those in FIG. 45 are denoted by the same reference numerals.

The features of the fixing plates 400 and 410 are that horizontal elongated holes 402 and 412 are formed respectively. The lens mount 378 (see FIG. 44) has a round elongated hole 40.
Round holes 378a and 378b corresponding to 2,412 are formed. When assembling the fixing plates 400 and 410 to the lens base 378, pins fixed to the holes 392 a and 394 a are inserted into the lens base 378 so as to have a desired design position. afterwards,
If adjustment movement is required in the asynchronous direction,
02, 412 and the positions of the round holes 392a, 394a are adjusted. This adjustment is performed by adjusting the round holes 402 and 412 and the round holes 392.
a, 394a with the eccentric pin 420 inserted. Thereby, the position can be adjusted while continuously moving the fixing plate. As shown in FIG. 47, the scale 4
Since the lens 22 is formed, the amount of movement can be adjusted, and the fixing plates 400 and 402 can be fixed at desired positions on the lens mount 378 while adjusting.

[0193]

As described above, according to the transport device provided in the image forming apparatus of the present invention, the downstream portion of the transport auxiliary member in the transport direction is positioned higher than the upstream portion in the transport direction. Therefore, no wrinkles occur on the recording paper in the downstream portion in the transport direction. In addition, since the upstream portion of the transport auxiliary member in the transport direction is low, the recording paper is hardly brought into contact with the transport paper, and a good transport force can be obtained.

Here, the transport assisting member is located at a position where the upstream portion of the transport assisting member in the transport direction is lower than the transport member, and the downstream portion of the transport assisting member is at a position higher than or the same height as the transport member. If it is located, wrinkles do not occur on the recording paper, and the conveying force is further improved.

Further, when the leading end of the minimum length recording paper conveyed by the conveyance device reaches the second area, the conveyance assisting member conveys the rear end of the recording paper or a portion more conveyed than this part. If the height is different on the upstream side in the direction, even the recording paper having the minimum length can be satisfactorily conveyed.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a copying machine as an embodiment of an image forming apparatus according to the present invention, showing an appearance when each door is closed.

FIG. 2 is a perspective view of the copying machine of FIG. 1 in which each door and the like are open, as viewed from the front.

FIG. 3A is a perspective view of the copying machine of FIG. 1 in which a paper discharge door is opened, as viewed from the side, and FIG. 3B is a diagram illustrating a state in which the paper discharge door is opened and a recording sheet is taken out from a duplex conveying unit. FIG. 4 is a perspective view schematically showing a state in which the camera is on.

FIG. 4 is a plan view showing an operation unit of the copying machine shown in FIG.

FIG. 5 is an explanatory diagram showing an example of changing an auto power off time.

FIG. 6 is an explanatory diagram showing a password input procedure.

FIG. 7 is a schematic diagram showing an internal structure of the copying machine of FIG.

FIG. 8 is a schematic diagram illustrating a conveyance path of a recording sheet.

FIG. 9 is a schematic diagram showing a drive system of each motor.

FIG. 10 is a perspective view showing components near a horizontal registration roller, a horizontal registration motor, and the like.

FIG. 11 is a schematic diagram showing a lateral registration sensor.

FIG. 12 is a schematic diagram showing a horizontal registration roller home position sensor.

13 (a) is a plan view and FIG. 13 (b) is a side view showing an oil absorbing pad housed in a pad holder.

FIG. 14 is a block diagram showing an electric circuit of the copying machine shown in FIG. 1;

FIG. 15 is a block diagram showing circuits related to a document illumination lamp and a fixing heater system.

FIG. 16 is a block diagram illustrating a control configuration of the copying machine of FIG. 1;

FIG. 17 is a schematic diagram illustrating a transport unit of the copying machine.

FIG. 18 is a schematic diagram illustrating two belts and a transport assisting member.

FIGS. 19A and 19B show a transport assisting member and two belts, and FIG.
Is a side view showing only the conveyance auxiliary member, (b) is a schematic view of the positional relationship between the two belts and the conveyance auxiliary member on the downstream side in the recording paper conveyance direction viewed from the conveyance direction, and (c) is an upstream in the recording paper conveyance direction. FIG. 6 is a schematic diagram illustrating a positional relationship between two belts and a transport assisting member on a side when viewed from a transport direction.

FIG. 20 is a schematic diagram illustrating a state in which a recording sheet of a minimum size among the recording sheets used in the copying machine is being conveyed.

FIG. 21 is a schematic diagram illustrating a configuration of a fixing device.

FIG. 22 is a timing chart illustrating temperature adjustment of the fixing device.

FIG. 23 is a perspective view schematically showing a schematic structure of a paper discharge unit.

FIG. 24 is a schematic diagram illustrating conveyance of a recording sheet.

FIG. 25 is a schematic diagram showing transmission of mechanical drive of each motor and each roller.

FIG. 26 is a block diagram illustrating a control circuit that controls a paper discharge motor.

FIG. 27 is a schematic diagram illustrating a state in which the leading end of a recording sheet is abutted against a stopped first setback roller to form a recording sheet loop.

FIG. 28 is a schematic diagram illustrating a state in which the lower and upper transport flappers are lowered and the first and second setback rollers are started to rotate.

FIG. 29 is a schematic diagram showing a state in which the leading end of the recording paper is located at a distance 1 from the first setback roller toward the exit side.

FIG. 30 is a schematic diagram illustrating a state where a second recording sheet has been sent to a lower conveyance unit.

FIG. 31 is a schematic diagram illustrating a state in which the leading end of a second recording sheet is abutted against a stopped first setback roller to form a loop of the second recording sheet.

FIG. 32 is a schematic diagram showing a state where the lower and upper transport flappers have been lowered and the first and second setback rollers have begun to rotate.

FIG. 33 is a schematic diagram showing a state in which the leading end of the second recording paper has come out of the first setback roller toward the exit side by a distance 1;

FIG. 34 is a schematic diagram illustrating a state in which the stacked recording paper is advanced and the first recording paper is detected by a lower conveyance exit sensor.

FIG. 35 is a schematic diagram illustrating a state in which the first sheet of recording paper has come out of the lower conveyance exit sensor.

FIG. 36 is a schematic diagram illustrating a state in which a lower conveyance exit sensor detects the leading end of a first recording sheet.

FIG. 37 is a schematic diagram showing a state where the lower conveyance flapper is lowered and first and second setback rollers are temporarily stopped.

FIG. 38 is a schematic diagram illustrating a state where the first recording paper and the second and subsequent recording papers are separated.

FIG. 39 is a schematic diagram showing a state where a first recording sheet has passed through a second setback roller.

FIG. 40 is a schematic diagram illustrating a state in which a re-feeding operation of a second recording sheet is started.

FIG. 41 is a perspective view showing a schematic configuration of a blank shutter unit.

FIG. 42 is a schematic view showing a state where a photosensitive drum is subjected to blank exposure.

43 is a perspective view showing a schematic configuration of the lens driving system shown in FIG. 5;

FIG. 44 is a plan view of the lens drive system of FIG. 43.

FIG. 45 is a plan view specifically showing a fixing plate of the lens driving system in FIG. 43.

FIG. 46 is a plan view showing a modification of the fixing plate of FIG. 45 in detail.

47 (a) is a front view, FIG. 47 (b) is a side view, and FIG. 47 (c) is a bottom view showing an eccentric pin.

[Explanation of symbols]

 Reference Signs List 10 copier 46 paper discharge door 164 fixing device 168 fixing roll 173 paper discharge unit 176 double-sided conveyance unit 216 oil absorption pad 218 pad holder 304 belt 306 conveyance auxiliary member 308 downstream part of conveyance auxiliary member 310 upstream part of conveyance auxiliary member 350 lens 352 rail 356 stepping motor 372 first fixed base 376 second fixed base

Continued on the front page (72) Inventor Akihito Nagayama 6-3-3 Shimorenjaku, Mitaka-shi, Tokyo Inside Copier Co., Ltd. (72) Inventor Otani Horie 6-3-3 Shimorenjaku, Mitaka-shi, Tokyo Co., Ltd. Shares Inside the company (72) Inventor Mitsunori Nakamura 6-3-3 Shimorenjaku, Mitaka-shi, Tokyo Copier Corporation (72) Inventor Satoru Kijima 6-3-3 Shimorenjaku, Mitaka-shi, Tokyo Copier Corporation (72 ) Inventor Kenji Nagata 6-3-3 Shimorenjaku, Mitaka City, Tokyo, Japan (72) Inventor Shuichi Endo 6-3-3 Shimorenjaku, Shimorenjaku, Mitaka City, Tokyo, Japan (72) Inventor Minowa Kensaku 6-3-3 Shimorenjaku, Mitaka-shi, Tokyo Inside of Kopia Co., Ltd.

Claims (3)

[Claims] 1. An image forming apparatus for forming an image on a recording sheet, comprising a conveying apparatus for conveying a recording sheet from a predetermined first area to a second area, wherein the conveying apparatus contacts the recording sheet while contacting the recording sheet. The recording paper is moved from the first area to the second area.
A pair of conveying members that are arranged in parallel at a predetermined interval to be conveyed to the area, and are arranged between the pair of conveying members and extend in the conveying direction. The downstream part in the conveying direction is more upstream than the upstream part in the conveying direction. An image forming apparatus comprising: a transport assisting member positioned at a high position. 2. The transport assisting member, wherein an upstream portion in the transport direction of the transport assisting member is located at a position lower than the transporting member, and a downstream portion in the transporting direction is located at a higher position or the same height as the transporting member. 2. The image forming apparatus according to claim 1, wherein the image forming apparatus is located at a position indicated by the arrow. 3. The transport assisting member according to claim 1, wherein, when a leading end of the minimum length recording paper transported by the transport device reaches the second area, a portion where the trailing edge of the recording paper is located or this portion. The image forming apparatus according to claim 1, wherein the height of the image forming apparatus is different on the upstream side in the transport direction.